How do you factor #x^3 + 13x^2 + 42x#?

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Answer 1 · 2016-07-04T08:44:35

=x(x+6)(x+7)

your expression is ;

#= x^3 +13x^2 + 42x#

Taking common from this expression :

#= x [x^2 + 13x + 42]#

Now getting the factors of 42 and seeing if the sum of its factors equals to 13 ( middle value).

By getting its factors (#7*6# = 42) we have come to know that 7 + 6 equals to 13.

#= x[x^2 + 7x + 6x + 42]#

#= x[x ( x+7) + 6 (x+7)]#

#= x[(x+6)(x+7)]#